A union has warned only half the Holden workforce is prepared to accept a new pay and conditions deal to see the struggling carmaker continue production at its Elizabeth plant in Adelaide.
The workers are to hold a secret ballot on the proposal next Tuesday.
Acceptance of giving up future pay rises and some working conditions will provide no guarantees, but a no vote will ensure the manufacturer's exit from Elizabeth.
Manufacturing Workers Union John Camillo said the detail of the offer left some employees unsure whether they should accept.
"There's still a lot of people that don't understand the variation because it's legal jargon for them and so that's why we've put a simplified newsletter out, two days ago," he said.
"They're reading that so they have different understanding of what's happening and we'll continue walking the shop floor, talking to those people and getting a feel for what the issues are."
The enterprise bargaining proposal makes demands on overtime and greater flexibility for Holden to sack underperforming workers.
"I've been a union official for 25 years, I've never come across anybody being dismissed for malingering," Mr Camillo said.
Federal Industry Minister Kim Carr said: "These are measures that apply largely at Toyota already."
The union said if the 1,700 workers rejected the Holden offer, the carmaker would close its Elizabeth operations in 2016.
Liberal Senator Simon Birmingham said the northern Adelaide region's Labor member, Nick Champion, should withdraw a statement in a letter sent to residents of the Wakefield electorate claiming he had secured Holden's future at Elizabeth until 2022.
Senator Birmingham said Holden's future remained unclear and Mr Champion needed to set the record straight.
"He's written to every voter in his electorate making this misleading claim," he said.
"He should write to them all again telling the truth for once and making it very clear that the Labor Party's policies around fringe benefits tax and the carbon tax are in fact hurting and jeopardising Holden's future."
Mr Champion cannot say how he has secured a guarantee of another nine years of production at the Holden Elizabeth plant, but claims any uncertainty over the carmaker's future is due to the Coalition's proposed assistance cut for the car industry.
"Holdens are responding to the uncertainty that's being produced by the Liberal Party's policy which is about cutting $500 million from automotive assistance and of course we're in the middle of an election campaign, we don't know the outcome of that campaign," he said.